The present invention relates to cutting tools and, more particularly, to cutter heads adapted to be rotatably driven by woodworking tools and mounting a plurality of blade members.
There are several types of woodworking tools designed specifically to shape a piece of wood stock so that its external surfaces are smooth, well-shaped and precisely angled to each other. One type of tool for performing such a function is a jointer. A jointer consists of a rotating cutter head positioned substantially below a workpiece-supporting surface. The supporting surface includes an infeed table, located upstream of the cutting tool, and an outfeed table, located downstream of the cutting tool and slightly above the infeed table.
The cutter head is motor-driven, cylindrical in shape, and rotates about an axis transverse to the direction of feed. The cutter head typically has between two and four blade slots formed in its outer surface and extending longitudinally of the cutter head. Each blade slot mounts a single cutter blade which is coextensive with the slot and typically is retained in the slot by a wedge which is screwed to the cutter head and urges the blade against a wall of the slot.
The cutter head is positioned such that the outer edges of the blades are at substantially the same elevation as the surface of the outfeed table. The blades of a typical cutter head for a jointer vary between 4" and 8" in length, and such a jointer is capable of making a depth of cut of not more than 3/8". In operation, a fence is attached to the infeed and outfeed tables and the workpiece fed across the table so that the rotating cutter head makes a smooth cut at an angle to the fence. Jointers typically are used for making a smooth and straight edge on a board which is square to the face of the stock and is suitable for making a joint with another, similarly shaped piece of stock.
A planer is another type of woodworking tool which utilizes a rotating cutter head, but performs an operation which is different from a jointer. A planer has a level workpiece-supporting surface which is positioned beneath a motor-driven cutter head that rotates about an axis transverse to the direction of feed. The workpiece is fed across the table, and the rotating cutter head planes the stock to a uniform thickness. Planers are used to reduce thick boards to thinner ones, surface rough lumber, square up stock, plane boards to identical thicknesses, and even the thickness of boards that have been glued edge-to-edge.
The cutter head of a planer is similar in construction to its counterpart in a jointer, except that the length of the planer cutter head usually is two to three times that of the jointer: typically 8" to 12". An example of such a planer is shown in the Buttke U.S. Pat. No. 2,792,036. That patent shows a planer in which the cutter head consists of a unitary, cylindrical member having three longitudinally-extending blade slots. The blades are mounted within these slots and are held in position by wedges which include adjustable screws that extend outwardly to push against an opposite wall of the blade slot from the blade, thereby clamping the blade against the slot.
A third type of woodworking tool used to shape a piece of wood stock is a molding cutter. A molding cutter is used to shape table edges, form cabinet door lips, make sash, and produce strong glue joints. The cutter head for a molding cutter is similar to the cutter heads for jointers and planers in that it is generally cylindrical and includes slots shaped to receive cutting blades. However, the molding cutter head is rather short and disk-shaped in comparison, typically 1" to 2" in length, and the cutting blades may have arcuate or eccentrically-shaped cutting surfaces. The molding cutter head typically is used with a table saw assembly and is mounted on the shaft that normally holds the circular saw blade. The cutting blades project upwardly through a slot in the table, and the workpiece is guided over them. An example of a cutter head for such a tool is shown in the Edgemond, Jr. U.S. Pat. No. 2,896,678.
In the manufacture of jointers and planers, the most expensive component is the cutter head assembly, which includes the cutter head, blades and wedge mechanisms for attaching the blades to the cutter head. This is also true in the manufacture of multipurpose woodworking tools such as, for example, the tool shown in the Edgemond, Jr. et al. U.S. Pat. No. 2,927,612. That tool includes a motor-driven headstock adapted to power a number of different tools, among them a jointer and a molding cutter. It is also known to use a planer attachment which is adapted to be mounted on such multipurpose tools and driven by the motorized headstock.
Presently, a manufacturer of two or more of the aforementioned cutting tools, or a manufacture of a multipurpose woodworking tool having two or more of the cutting tools, must manufacture a specific cutter head for each type of cutting tool. The necessity of having to manufacture several types of cutter heads adds a significant expense to the overall cost of production for that manufacturer. There presently is no single cutter head in use which can be adapted to be used with either a jointer, a planer or a molding cutter.
Accordingly, there is a need for a cutter head system which is capable of being modified to function as a cutter head for a jointer, planer or molding cutter. However, such a cutter head system should be sufficiently precise to provide the relatively close cutting tolerances required of such woodworking tools.